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to Teflubenzuron Index Page
Activity:
Insecticide
(benzoylurea)
Structure:
Adverse Effects:
Liver
Lymph
node haemangiomas
Pancreas
Environmental
Teflubenzuron
is an acyl urea derivate classified as an insecticide for
use in treatment of infestation with sea lice in salmon.
Teflubenzuron is admixed with pelleted diet at a level of
2 g/kg. The intended dosage level of teflubenzuron is 10
mg/kg bw administered once daily for 7 consecutive days.
The substance is also used as a pesticide on crops. Very
few substances are available for treatment of sea lice in
salmon...
January
1999 - Summary Report. Committee for Veterinary Medicinal
Products. The European Agency for the Evaluation of Medicinal
Products.
http://www.fluoridealert.org/pesticides/teflubenzuron.review.1999.pdf
There
is very little information available on the environmental
fate and ecological effects of teflubenzuron in aquatic
environments. The specific mode of action of teflubenzuron
means it is highly toxic to aquatic
crustacean invertebrates, but low in toxicity to
fish, mammals and birds. As with emamectin benzoate, it
is likely that the sediments will
act as a sink for teflubenzuron and so sediment associated
organisms are more likely to be affected by this chemical...
Ref:
Calicide (Teflubenzuron) - Authorisation for use as an in-
feed sea lice treatment in marine cage salmon farms. Risk
Assessment, EQS and Recommendations (As agreed at the Board
Meeting held on 7 th July, 1998 and subsequently updated
in July, 1999). Policy No. 29. SCOTTISH ENVIRONMENT PROTECTION
AGENCY. Fish Farming Advisory Group.
http://www.fluorideaction.org/pesticides/teflubenzuron.scotlandepa99.pdf
TOXIC
chemicals used on salmon farms could be killing off key
elements of the marine food chain, according to a report
leaked to a leading scientific magazine. ÔNew
ScientistÕ magazine has obtained a copy of a 178-page report
which forms part of the ongoing £4 million study into the
industry, which was launched by the UK government in 1999.
In the leaked document it is alleged that chemicals such
as cypermethrin, azamethiphos or
teflubenzuron are damaging small crustaceans and other marine
wildlife, which could be crucial to the survival of other
species. These chemicals are often used by farmers
to rid fish of sea lice.
See also April 25, 2002
press release from Friends of the Earth, Scotland.
Ref: Leaked
Report Claims Toxins Are Hitting Marine Food Chain Fish
Farming Today- Fish Farming Today. April 25, 2002
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Liver
(click on for all fluorinated pesticides)
-- Short term repeat
dose toxiciity tests in rats, mice and dogs revealed that the
major target organ for the toxic effect of teflubenzuron is the
liver. The main findings attributed to hepatoxiciity were
increased liver weights and liver lesions, such as
hepatocellular swellings, collapsed stroma, fatty changes, necrosis
and cell infilitration.
-- In a 18-month carcinogenicity study in mice, teflubenzuron
was given via the diet at concentrations of 0, 15, 75 or 375 mg/kg
feed, equal to 0, 2.1, 10.5 or 53.6 mg/kg
bw/day in males and 0, 3.1, 15.4 or 71.7 mg/kg bw/day in females...
Non-neoplastic dose-dependent hepatic changes were observed in
both sexes of all treated groups, such as hypertrophy,
hyperplasia, single cell necrosis, phagocytic cell foci, lipofuscin
accumulation and glycogen storage. The incidence of hepatocellular
adenomas at 18 months (terminal kill) was
significantly increased in males at
the two highest dose groups: 22%
in the mid-dose group and 32% in the high dose group versus 12%
in the concurrent control group and 16% in the historical control
group. There were no changes in the incidence of hepatocellular
carcinomas. Since the increased incidence of hepatocellular adenomas
is likely to be secondary to the hepatoxicity of teflubenzuron
and was of a type generally not considered to be of concern for
human health if not accompanied by other evidence for carcinogenicity,
the mouse study was considered not to provide evidence for carcinogenicity
of teflubenzuron.
-- The FAO/WHO Joint Meeting on Pesticides Residues (JMPR) evaluated
teflubenzuron in 1994 and established an ADI of 0.01 mg/kg bw/day,
based on the dose-related effects in the target tissue
liver in the mouse carcinogenicity study submitted.
January 1999 - Summary Report. Committee
for Veterinary Medicinal Products. The European Agency for the
Evaluation of Medicinal Products.
http://www.fluoridealert.org/pesticides/teflubenzuron.review.1999.pdf
Lymph
node haemangiomas
(click
on for all fluorinated pesticides)
-- In a 120-week long-term
toxicity/carcinogenicity study, rats were fed diets containing
0, 20, 100 or 500 mg/kg feed, equal to 0, 1, 4.8 or 24.8 mg/kg
bw/day in males and 0, 1.2, 5.9 and 29.9 mg/kg bw/day in females...
Histopathological examination indicated an increased incidence
of mesenteric lymph node haemangiomas
in males in the high dose group (17%) in comparison with rats
in concurrent controls (2%), but not when compared to the incidence
in historical controls. A significantly
increased incidence of pancreatic exocine carcinomas in male rats
in the high dose group (4.3%), compared to concurrent controls
(0 out of 50) and historical control groups (1.4% or 1 out of
69), was based on a low number of affected rats (2 out
of 47) and was therefore not considered to be treatment related.
January 1999 - Summary Report. Committee
for Veterinary Medicinal Products. The European Agency for the
Evaluation of Medicinal Products.
http://www.fluoridealert.org/pesticides/teflubenzuron.review.1999.pdf
Pancreas
(click
on for all fluorinated pesticides)
-- In a 120-week long-term toxicity/carcinogenicity study, rats
were fed diets containing 0, 20, 100 or 500 mg/kg feed, equal
to 0, 1, 4.8 or 24.8 mg/kg bw/day in males and 0, 1.2, 5.9 and
29.9 mg/kg bw/day in females... Histopathological examination
indicated an increased incidence of mesenteric lymph node haemangiomas
in males in the high dose group (17%) in comparison with rats
in concurrent controls (2%), but not when compared to the incidence
in historical controls. A significantly
increased incidence of pancreatic exocine carcinomas in male rats
in the high dose group (4.3%), compared to concurrent controls
(0 out of 50) and historical control groups (1.4% or 1 out of
69), was based on a low number of affected rats (2 out of 47)
and was therefore not considered to be treatment related.
Ref: January 1999 - Summary Report. Committee
for Veterinary Medicinal Products. The European Agency for the
Evaluation of Medicinal Products.
http://www.fluoridealert.org/pesticides/teflubenzuron.review.1999.pdf
Environmental
(click
on for all fluorinated pesticides)
TOXIC
chemicals used on salmon farms could be killing off key
elements of the marine food chain, according to a report
leaked to a leading scientific magazine. ÔNew
ScientistÕ magazine has obtained a copy of a 178-page report
which forms part of the ongoing £4 million study into the
industry, which was launched by the UK government in 1999.
In the leaked document it is alleged that chemicals such
as cypermethrin, azamethiphos or
teflubenzuron are damaging small crustaceans and other marine
wildlife, which could be crucial to the survival of other
species. These chemicals are often used by farmers
to rid fish of sea lice.
- See also April 25, 2002
press release from Friends of the Earth, Scotland.
Ref: Leaked
Report Claims Toxins Are Hitting Marine Food Chain Fish
Farming Today- Fish Farming Today. April 25, 2002
--
There is very little information available on the environmental
fate and ecological effects of teflubenzuron in aquatic
environments. The specific mode of action of teflubenzuron
means it is highly toxic to aquatic
crustacean invertebrates, but low in toxicity to
fish, mammals and birds. As with emamectin benzoate, it
is likely that the sediments will
act as a sink for teflubenzuron and so sediment associated
organisms are more likely to be affected by this chemical.
-- It
is difficult to predict the ecological risk of teflubenzuron
to the marine environment because of the current lack of
information. Results from field studies referred to in SEPAÕs
environmental risk assessment suggest
that the use of teflubenzuron for sea lice control may present
a moderate to high environmental risk. It seems unlikely
that teflubenzuron will be widely used for sea lice control
in Scotland, but if use does increase, investigation into
the potential long-term impacts of this chemical on the
marine environment is recommended.
Ref:
REVIEW AND SYNTHESIS OF THE ENVIRONMENTAL IMPACTS OF AQUACULTURE.
The Scottish Association for Marine Science and Napier University.
Scottish Executive Central Research Unit. 2002.
http://www.scotland.gov.uk/cru/kd01/green/reia.pdf
Although
teflubenzuron is relatively non-toxic to most marine species
(e.g. fish, algae, shellfish), it
is potentially highly toxic to any species which undergo
moulting within their life cycle. This will therefore include
some commercially important marine animals such as lobster,
crab, shrimp and some zooplankton species.
Subsequent chemical analysis confirmed that measurable
concentrations were generally not present in water after
treatment and that levels in sediments were variable but
followed the predicted dispersion model with measured levels
of teflubenzuron extending initially to about 50m from cages
in line with the main direction of current.
In the study, teflubenzuron was found to persist longer
than 6 months, which was longer than expected and
hence additional studies were commissioned by Nutreco at
the request of SEPA and VMD. The predicted half-life of
teflubenzuron in sediment was from 8 to 92 days depending
on sediment type (Myrvold, 1997) and it had been expected
that 90% of teflubenzuron should have been degraded within
6 months. The indication of a potential for longer persistence
is attributed to the site being a ieworst casels site already
enriched and impacted by organic wastes with teflubenzuron
being retained by binding with organic material (Trouw,
1999). The results from long-term site monitoring finally
reported a half life of 104 to 123
days (Trouw, 1999). From this data, SEPA now intend
to apply a half life of 115 days as a decay factor when
undertaking site loading calculations for consent applications
or reviews.
Chemical analysis of samples collected on-site of indigenous
crustacea was also undertaken. It was concluded that there
was a risk that sediment dwelling crustacea, such as edible
crab (Cancer) and possibly Norwegian lobster (Nephrops),
may accumulate teflubenzuron from contaminated sediment.
However, it is known that depuration and loss of teflubenzuron
does proceed following initial exposure and uptake (McHenery,
1997) and hence levels may be lost from such species before
toxic effects occur (moulting).
The
half-life of teflubenzuron in sediment suggests that there
is a moderate risk of build up in sediment through repeat
applications,
although the risk of this is reduced where fewer applications
are required by correct use of the product strategy.
Ref:
Calicide (Teflubenzuron) - Authorisation for use as an in-
feed sea lice treatment in marine cage salmon farms. Risk
Assessment, EQS and Recommendations (As agreed at the Board
Meeting held on 7 th July, 1998 and subsequently updated
in July, 1999). Policy No. 29. SCOTTISH ENVIRONMENT PROTECTION
AGENCY. Fish Farming Advisory Group.
http://www.fluorideaction.org/pesticides/teflubenzuron.scotlandepa99.pdf
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